Discussion of Ventilators, PPE, Face Shields, etc

There have been a number of threads popping up lately with regards to building ventilators, face masks, etc., and we’d like to share what the moderators have come up with for guidelines as to what discussion is allowed on the site (for safety reasons, among others):

  • Discussion of the proper use of PPE is 100% okay.
  • Discussion of face shield development is 100% okay.
  • Discussion of uncertified face mask development is okay , as long as it is clear they are uncertified. The effectiveness of such masks is debated within the medical community.
  • Discussion of building homemade versions of more sophisticated equipment like ventilators is not allowed on safety grounds, with two exceptions:
    • Discussion of projects that are in or clearly nearing government review, such as AmboVent or MIT’s E-Vent
    • Sourcing requests for specific parts (e.g. “I need a power supply” or “I need a fab shop that can do X”, not “I want the parts to build a ventilator, where do I go?”)

Thank you for helping us keep the discussion of these very important initiatives in alignment with the above rules.

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Huzzah! Ya’ll are the best.

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And if there’s an existing thread in which you can put your post, please do that. We don’t need 47 teams all starting an individual thread about how they are 3D printing face masks.

If it’s something unique, then sure, make a new thread about it.

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Thank you Brandon and fellow moderators who worked together to get this figured out.

In addition I created messaging on FUN content discussing what FIRST teams can do to help their communities (and what to stay away from as well).

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This video was really interesting to get a little more understanding of how ventilators work and some of the things that need to be considered for any given design. There are a lot of very important considerations he touches on here that just go to show why ventilators should be left to the professionals.

Real Engineering: Guide to Designing Ventilators (aka Why You Shouldn’t)

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For those of you who can had a robot fail this season more than 1 out of 10 matches and are sure you won’t solve the technical issues with a student built ventilator, consider this option for helping your at risk community members. It has the added benefit of preventing the need for a ventilator. Another person mentioned helping at a hospital for an easily cleaned delivery device as well.

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I think this falls under “face shield development”, understanding face shields to be cloth or similar structures over the nose and mouth to reduce the number of viruses you may spread as a pre-symptomatic or non-symptomatic carrier. [As an aside, if you have a pollen or smoke allergy the face shield may also catch some pollen/smoke, reducing or eliminating sneezes, to the great ease of all around you.]

Background: I am a US Navy civilian employee working mostly (60-75%) at the office, with some (20-30%) telework, and the remainder leave (mostly admin for health & safety, some personal so I can work at home and shop during business hours because of a curfew). This week, as recommended by the CDC and the Department of Defense, I began wearing homemade cloth face shields to work. While I am in my office alone most of the day, I spent about 3 to 6 hours within 10 feet and about 2-3 hours within 6 feet of someone else, 'cause that’s part of my job to enable others. In abundance of caution, I kept it on when at the office except at lunch (which I ate in my car in the parking lot) or for short periods in my office either while the door was closed or I was taking a brief sip from my coffee mug (which I only did when no one was in or near my office door).

Problem: The biggest problem I encountered using the cloth face shield was that my breath would slip out the space between my nose and cheekbones, enter the area between my eyes and glasses (spectacles), and fog the glasses. Logically, should I also happen to be unknowingly COVID-19 infected, this would allow a path for water droplets with the virus to spread.

Solutions:
My initial solution was to twist the elastics around, so the elastic stress going over my nose went under my ear, and that going under my chin when over my ear. Better in terms of fog in my glasses, but far from comfortable, at least as the shields I used were built.

After seeing small metal plates on some fancier shields and masks today, I thought about sewing similar metal plates into my face shield. A few minutes later, I realized that all I needed was a bit of wire. I removed an approximately 8" piece of wire from an old coffee twist tie that was in my office, and inserted it into the top seam of my face shield. A few minutes of adjustment later, I was working fog-free!

The wire I used was similar in properties to fine floral wire. If you can get solid core aluminum wire in the 16-20AWG range, this would:

  • be easy to insert into face shields
  • provide a good balance of stiffness vs pliability
  • not rust when you wash the mask in soap and water to prepare it for re-use as recommended by the CDC

Hoping this helps!

On another front: I actually found 60+% ethanol hand sanitizer at my local grocery store today! I bought the (limit of) 2, one for my car, and one for @PereBear’s. (We’re both still working outside the home, and this is when you most need a non-soap solution in that situation!)

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Like quite a few people I was asked to look at the issue of ventilators, but pretty quickly realized that the core issue wasn’t whether engineering was possible but whether production was viable before the peaks of need related to Covid-19 in the US. It wasn’t long before I realized it wasn’t practical to try to do this properly and could produce serious harm to patients. Still I did other things to help that were much more practical.

Around 7:53 that video really gets to the meat of the problem with the bag squeezing mechanism. On the one hand this video is really good because it’s focused on the core issues by those experienced in the matter. On the other, I did notice that what the video did not do is:

  1. More fully explore older methods of building ventilators which obviously had less fancy controls.

  2. Didn’t discuss the different air sources used in ventilator designs like: turbine, piston pumps, or ascending or descending bellow pumps (as pictured at: 12:23 in this video).

  3. Did mention pressure/volume/flow control but not the 3rd mode where the machine pushes some small flow at all times like a CPAP.

  4. Didn’t mention oximeters.

  5. It did mention humidification but it didn’t mention the issues that humidifying the air in the lines creates.

  6. It didn’t mention the outcomes that a lot of Covid-19 patients that require a ventilator often experience. I could cite some evidence if asked, but unlike other ventilator users where < 40% don’t recover. Covid-19 patients are much more likely once on a ventilator to remain there unfortunately. It seems oxygen treatments help but once a patient is intubated now you need to mess with getting them oxygen not just normal atmospheric gas (which includes nitrogen, carbon dioxide…). I really don’t think people should be tinkering casually with compressed oxygen where a little bit of grease in the wrong place can result in catastrophic outcomes.

I’ve seen lots of posts from experienced people suggesting this problem is not as simple as it would appear. My post is not to encourage people to continue, in fact it’s timed essentially to avoid that hasty outcome, but to encourage people to learn more about the mechanisms and controls in the hope that future engineers will be inspired.

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